This invention relates in general to hinge systems and, more specifically, to hinge systems for pivoting curved structures about a straight hinge line in applications such as engine thrust reverser systems.
A wide variety of hinge systems have been developed for allowing one structure, such as a lid or door, to pivot relative to a box or cabinet. Two or more hinges are generally used with individual hinge lines lying along a straight line running through all of the individual hinge lines about which the moving part pivots. Some are surface mounted, others are hidden, but they have this single overall hinge line in common.
A number of different arrangements have been developed for mounting jet engines on aircraft using latches or pivoting means to assist in mounting and removal of the engine and to accommodate differential thermal expansion of the engine and supporting structure, often a pylon, during use. Typical of these are the systems described by Dolgy et al in U.S. Pat, No. 3,809,340 and Chee in U.S. Pat. No. 4,603,822. These all use mounting means arranged in a single position or along straight lines.
Various over-center hinges and tensioning devices using multiple links have been developed for special purposes, such as the band tensioning device of Aspinall as described in U.S. Pat. No. 4,557,44. No application of such links to the support of structures is shown.
A variety of removable access panels are often provided in order to permit examination and repair of internal components of large jet engines and the like. These panels are generally in the form of small panels held to the engine cowl by screws or other fasteners. In some cases, hinged panels are used, where a straight hinge line can be provided. No fully satisfactory arrangement exists for hingedly moving a large cowl panel, such as covers the thrust reverser, where the panel edge does not lie along a straight hinge line. With cascade type thrust reversers, it is desirable that the cowl be split at the bottom, opposite the pylon, and be hingedly mounted at the pylon to permit access to internal components, such as thrust reversers. The cowl of a modern jet engine tends to be continuously curved, making hinging of a such a pane difficult.
Thus, there is a continuing need for improved hinge systems that can accommodate a non-straight hinge line, can accommodate changes in the distance between hinges caused by differential thermal expansion and can support large and heavy structures, such as jet engine cowl sections.